科研之友
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摘要
In this study, we developed a new type of composite membrane to mitigate oil fouling in membrane distillation (MD). The composite membrane consists of a polytetrafluoroethylene (PTFE) hydrophobic substrate and a hydrophilic poly(vinyl alcohol)/silica nanoparticles (PVA-Si) hybrid fibrous coating prepared via sol-gel and electrospinning. We characterized the pristine PTFE membrane and the modified membrane using contact angle measurements and tensiometer-based oil probe force spectroscopy. While the hydrophilic coating presented excellent oil fouling resistance, the glutaraldehyde cross-linking treatment augmented the in-air hydrophilicity and underwater superoleophobicity of the electrospun coating surface. The cross-linking treatment also prevented the formation of PVA-Si hydrogels for the electrospun hybrid fibers, which made availability to utilize the water-soluble polymer to modify hydrophobic membrane for anti-oil-fouling MD. By comparing the performance of the composite membrane and the pristine PTFE membrane in MD desalination experiments using a saline emulsion with 1000 mg/L crude oil, it showed that the fabricated composite membrane was significantly more resistant to oil-fouling compared to the PTFE membrane. The results from this study suggest that underwater superoleophobic coating can effectively mitigate oil fouling in MD, and that the fabricated composite membrane can enable MD to desalinate hypersaline wastewater with high concentrations of hydrophobic contaminants.
